A bus carrying 37 children crashed in Chattanooga on Tuesday afternoon, killing five children and sending 24 to the hospital with moderate to severe injuries. Johnthony Walker was behind the wheel, a 24 year-old bus driver for Woodmore Elementary School.

“Our hearts go out, as well as the heart’s of all the people around me, to the family, the neighborhood, the school and all the people involved in this,” Chattanooga Police Chief Fred Fletcher told reporters at a press conference on Monday. “We assure you we’re doing everything we can to help everybody be as safe as they can, get the care they need and get the support they need.”

The bus hit a tree, flipped over and split in half at approximately 3:20 p.m. The National Transportation Safety Board will send experts to examine the crash site. A warrant has been issued to obtain the black box and video from the bus.

Little is known about Walker’s history. The local police department hasn’t released any of his background information yet, but he is being charged with reckless endangerment and reckless driving. The 24 year-old could face more charges if drugs or alcohol were involved. He is currently being held in the Hamilton County jail on $20,000 bail and will appear in court on Nov. 29.

Police say Walker cooperated with authorities and is in custody. They haven’t revealed how long he’s worked for Woodmore Elementary School. Walker graduated from Brainerd High School in 2011, a public high school in Chattanooga.

“As the agency responsible for the School Resource Officer program in Hamilton County, my staff and I are deeply saddened by the loss of these young children,” Hamilton County Sheriff Jim Hammond said on Monday. “There are several families in our County that will not have their loved ones come home tonight and we as a community will feel the sadness and hurt from this event for a very long time to come. I am very proud of the Chattanooga firefighters, police officers, and Hamilton County EMS personnel who helped to rescue the injured. I am also very proud of the members of the HCSO who worked alongside our city first responders.”